I've got a clean installation of OS X Lion and I'd like to start using the default instance of Apache2 that comes installed. I've started Apache and placed a dummy index.html file in both /Library/WebServer/Documents and /Users/username/Sites, but when I navigate to http://localhost/ or http://localhost/~username/ I get a 404 Not Found error.

I've checked my /etc/Apache2/httpd.conf and /etc/Apache2/users/username.conf file and everything is pointing to the right directories, but no matter what I do I can not get it to serve the files located there. Can any one shed some light on the situation and tell me what I'm possibly doing wrong?